Conventional space-based imaging systems use push-broom imaging techniques in which a linear sensor array builds up a full frame image line-by-line as an associated platform moves/scans over a target. In such systems, a certain amount of geometric distortion is present in the final image as a result of the inability to perfectly control the motion of the platform during the scan period. For these push-broom systems, the attitude of the spaced-based platform is directly correlated to the “scan-line”. Further, the line-time, platform-velocity, and thus each projected line on the target, are all correlated. As a result, simple “line-time” iteration is generally sufficient to retrieve an unambiguous position of a pixel in the distorted image space, and produce a correction. The correction may then be used to resample the collected image data to obtain a corrected full frame image.
The use of framing sensors on space-based platforms to produce full-motion video is becoming more common. These framing sensors can generally be classified as a “rolling-shutter” type or a “global-shutter” type. Conventional space-based systems using framing sensors utilize “global” shutters, meaning that the entire image frame is captured simultaneously. While global-shutter type sensors produce images that are relatively unaffected by platform motion, global-shutter type sensors are traditionally more costly than rolling-shutter type sensors. Accordingly, rolling-shutter framing sensors are an appealing option for certain applications. However, the use of rolling-shutter framing sensors introduces unique geometric distortion that is more complex than that experienced by traditional push-broom sensors.